BRIEF COMMUNICATION Human Optimal Functioning: The Genetics of Positive Orientation Towards Self, Life, and the Future Gian Vittorio Caprara Æ Corrado Fagnani Æ Guido Alessandri Æ Patrizia Steca Æ Antonella Gigantesco Æ Luigi Luca Cavalli Sforza Æ Maria Antonietta Stazi Received: 7 November 2008 / Accepted: 18 March 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Certain personality characteristics such as self- esteem, life satisfaction, and optimism are fundamental components of positive mental health status and well- being. There is consistent evidence that these traits tend to be substantially correlated in individuals. However, no previous studies have investigated the origin of such cor- relation. This research used the twin method to unravel the genetic and environmental architecture of self-esteem, life satisfaction, and optimism, along with their mutual inter- play. The sample was derived from the population-based Italian Twin Register, and included 428 twin pairs, aged 23–24 years. Multivariate genetic modeling showed that genes influencing self-esteem, life satisfaction, and opti- mism are largely overlapping. Furthermore, results indi- cated that the environmental components of the traits may overlap only modestly, and suggested that a sizeable amount of variance in the traits may be explained by environmental effects specific to each of them. Keywords Positive orientation Á Self-esteem Á Life satisfaction Á Optimism Á Twins Á Heritability Introduction The view of positive mental health, advocated by WHO, as ‘‘a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community’’ (World Health Organization 2004), has led to focus on personal strengths and potentials no less than on the various features and sources of illness. The novelty in this field is the rejection of the traditional conceptualization of well-being and ill-being as the extremes of a continuum (Ryff et al. 2006). This calls for a strong commitment of both scholars and practitioners to the identification of factors which may contribute to positive mental health or well-being, to serve in the design of interventions, and ultimately to orient public policies in a large variety of domains such as health care, work organization, and family life. Several constructs have been proposed as appropriate and useful indicators of individual well-being, and among these, self-esteem, life satisfaction, and optimism have been demonstrated to be the most important components (Carver and Scheier 2002; Diener et al. 2002; Harter 2006; Kahneman et al. 1999). Since these constructs are sub- stantially correlated in individuals (Diener and Diener 1995; Schimmack and Diener 2003), it was suggested by non-genetic studies that a common high-order factor could explain the phenotypic variance shared among these char- acteristics (Caprara and Steca 2005, 2006). This compo- nent showed high stability across time and substantial correlation with various indicators of psychological well- being. Thus, it has been interpreted as an individual propensity to positively evaluate, or to be positively ‘‘ori- ented’’ toward various life domains including oneself, and one’s future and past experiences (Caprara and Steca 2005, G. V. Caprara (&) Á G. Alessandri Psychology Department, ‘‘Sapienza’’ University of Rome, Via dei Marsi 78, 00185 Rome, Italy e-mail: gianvittorio.caprara@uniroma1.it C. Fagnani Á A. Gigantesco Á M. A. Stazi Istituto Superiore di Sanita `, Rome, Italy P. Steca University of Milan ‘‘Bicocca’’, Milan, Italy L. L. C. Sforza Stanford University, Stanford, CA, USA 123 Behav Genet DOI 10.1007/s10519-009-9267-y